Anyone know any tricks for getting a new compressedtire back into shape

Changing a tire on my lawnmower. New tire compressed during shipping. Let sit out overnight still odd shape. Bead too far from rim to inflate. Tried putting tire in front of heater to warm it up. Didn’t help. Have sitting in sun, Hope this helps this afternoon.

Anyone have any tricks for getting tires close enough back into shape to mount. Tried spraying starter fluid around rim and igniting, gap too large to seal